Siarkou Victoria I, Vitti Danai, Protonotariou Efthimia, Ikonomidis Alexandros, Sofianou Danai
Laboratory of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Antimicrob Agents Chemother. 2009 Apr;53(4):1325-30. doi: 10.1128/AAC.01230-08. Epub 2009 Jan 21.
A study was designed to investigate the molecular epidemiological characteristics of multidrug-resistant outbreak-related Pseudomonas aeruginosa isolates collected in a university hospital in northern Greece. Of 29 nonreplicate P. aeruginosa isolates resistant to carbapenems and ceftazidime, 14 were positive for metallo-beta-lactamase production. PCR analyses with primers specific for bla(VIM) and bla(IMP) revealed that 13 isolates carried a novel bla(VIM-2) gene variant, designated bla(VIM-17), and only 1 isolate carried bla(VIM-2), a gene predominant among P. aeruginosa strains in Greek hospitals. Pulsed-field gel electrophoresis of XbaI-digested genomic DNAs showed a close genetic relationship for 12 of 13 bla(VIM-17)-carrying outbreak-related isolates, which were of the O11 serotype; the clonally unrelated isolate carrying bla(VIM-17) was of the O12 serotype. PCR mapping strategies for the detection of class 1 integrons and sequencing approaches revealed the presence of integrons containing one bla(VIM) cassette flanked by two aacA29 cassettes. These integrons were similar but not identical to In59 (GenBank accession number AF263519) initially described in France. All isolates carrying bla(VIM-17), regardless of their genetic profile, had an identical integron, named In59.3, indicating that although the hospital outbreak was mainly due to clonal dissemination, the horizontal transmission of the bla(VIM-17)-containing integron among P. aeruginosa isolates should also have occurred. An outbreak-related isolate and a control strain, both of which carried the bla(VIM-2) gene but which were clonally distinct, had an identical integron, named In59.2, which differed only at the level of the bla(VIM) gene from In59.3 integrons, suggesting a common ancestry. The spread of the bla(VIM-17)-containing integron in clonally unrelated P. aeruginosa isolates without any evidence of plasmid carriage is probably associated with a transposon.
一项研究旨在调查在希腊北部一家大学医院收集的与多重耐药性暴发相关的铜绿假单胞菌分离株的分子流行病学特征。在29株对碳青霉烯类和头孢他啶耐药的非重复铜绿假单胞菌分离株中，14株产金属β-内酰胺酶呈阳性。用针对bla(VIM)和bla(IMP)的特异性引物进行PCR分析显示，13株分离株携带一种新的bla(VIM-2)基因变体，命名为bla(VIM-17)，只有1株携带bla(VIM-2)，该基因在希腊医院的铜绿假单胞菌菌株中占主导地位。用XbaI消化的基因组DNA进行脉冲场凝胶电泳显示，13株携带bla(VIM-17)的与暴发相关的分离株中有12株具有密切的遗传关系，它们属于O11血清型；携带bla(VIM-17)的克隆无关分离株属于O12血清型。用于检测1类整合子的PCR定位策略和测序方法显示存在整合子，其包含一个由两个aacA29盒侧翼的bla(VIM)盒。这些整合子与最初在法国描述的In59(GenBank登录号AF263519)相似但不相同。所有携带bla(VIM-17)的分离株，无论其基因图谱如何，都有一个相同的整合子，命名为In59.3，这表明尽管医院暴发主要是由于克隆传播，但含bla(VIM-17)的整合子在铜绿假单胞菌分离株之间的水平传播也应该发生过。一株与暴发相关的分离株和一株对照菌株，两者都携带bla(VIM-2)基因但克隆不同，有一个相同的整合子，命名为In59.2，它与In59.3整合子仅在bla(VIM)基因水平上不同，表明有共同的祖先。含bla(VIM-17)的整合子在无任何质粒携带证据的克隆无关的铜绿假单胞菌分离株中的传播可能与转座子有关。
